Final answer:
In a closed-head injury with increased ICP and decreased MAP, a paramedic can expect cerebral blood flow to decrease, potentially leading to brain tissue damage and function loss.
Step-by-step explanation:
When a patient experiences a closed-head injury with increasing intracranial pressure (ICP) and a decrease in mean arterial pressure (MAP), one can expect a decrease in cerebral blood flow (CBF). The normal ICP is 5- to 12-mm Hg, and this pressure allows for the cerebrospinal fluid (CSF) to provide necessary flotation to the brain, nearly balancing the brain's weight. However, an increase in ICP, as seen with head injuries, can lead to constricted blood vessels, which together with a decreased MAP, can reduce the blood flow to the brain.
A condition such as hemorrhagic stroke, where there is bleeding into the brain, can also raise the ICP, with the accumulated blood exerting physical pressure on the brain tissue. This pressure can reduce local artery function and cause compromised blood flow, leading to function loss and potential neuronal damage. Thus, the answer to the question is A. The patient's cerebral blood flow decreases.